【作者】 丁小霞；

【导师】 李培武；

【作者基本信息】 中国农业科学院 ， 农产品质量与食物安全， 2011， 博士

【摘要】 花生是中国主要油料作物和纯出口优势农产品,总产居中国油料作物首位,是食油兼用型经济作物,在中国具有重要地位。然而近年来黄曲霉毒素污染严重威胁花生安全消费和国际贸易,已成为制约中国花生消费安全和产业发展的重大风险隐患。因此,开展花生黄曲霉毒素污染状况研究,建立花生黄曲霉毒素风险评估技术,对花生等主要农产品质量安全监管、保障安全消费,以及标准制修订和国际贸易等都具有重要意义。本论文首次对中国产后花生黄曲霉毒素污染分布状况进行了系统研究,在全国13个花生主产省抽取2571份代表性产后花生样品采用国际先进的免疫亲和层析液相色谱法进行了检测分析,样品覆盖中国花生生产面积的90%。探明了中国产后花生黄曲霉毒素污染分量、总量、地域分布与污染特征。并基于中国产后花生黄曲霉毒素污染状况和中国人群花生消费情况,建立了以花生黄曲霉毒素污染痕量数据取值方法、非参数定量概率评估技术为核心的既符合国际通行规则,又适于中国花生黄曲霉毒素污染状况的风险评估技术,对中国产后花生黄曲霉毒素膳食摄入风险进行了评估,为我国花生等农产品质量安全监管、标准制修订、国际贸易等提供关键技术支撑。主要研究方法与研究结果如下。1.首次探明了我国产后花生黄曲霉毒素污染分布,构建了花生黄曲霉毒素污染数据库。采用分层随机抽样方法连续2年从全国花生主产区抽取代表性产后花生样品2571份,采用国际先进的免疫亲和层析-液相色谱方法检测分析了黄曲霉毒素含量,获得黄曲霉毒素污染检测数据12855个,建立了基于微软.net framework 2.0框架和SQLite的中国产后花生黄曲霉毒素污染数据库,具有信息录入、修改、浏览、查询、数据导入导出、密码安全等9大功能和占用资源低,维护难度小的特点,可简单快速的实现与@risk等风险评估软件对接,用于花生黄曲霉毒素污染分布分析和黄曲霉毒素风险评估。探明了AFB₁是中国产后花生黄曲霉毒素污染的主要成分,占黄曲霉毒素总量的百分比平均值为86.2%,与黄曲霉毒素总量相关系数达0.99。安徽省产后花生AFB1污染最重,辽宁省最轻;长江流域主产区产后花生黄曲霉毒素污染最重,东北主产区产后花生污染最轻;中国产后花生黄曲霉毒素污染呈现明显的地域特征;污染严重地区有向北方蔓延的趋势。2.研究建立了以0与LOD点值替代的痕量数据取值方法、非参数概率评估技术为核心的中国花生黄曲霉毒素膳食暴露评估技术。探明了黄曲霉毒素检测方法及其检出限是黄曲霉毒素污染痕量数据取值关键限制因子,对0,1/2LOD,LOD等点值替代法和皮尔逊分布、对数正态分布等37种分布替代法优化筛选基础上,建立了以免疫亲和层析-高效液相色谱检测方法为基础,“0”与“LOD”点值替代的黄曲霉毒素污染痕量数据取值方法。基于0和LOD点值替代痕量数据取值方法,建立了配套的非参数概率评估技术,优化确定非参数概率评估迭代模拟次数为30000次,抽样次数为1000次。采用建立的非参数概率评估方法评估了中国人群产后花生黄曲霉毒素膳食暴露量,儿童属于产后花生黄曲霉毒素高暴露人群,其黄曲霉毒素膳食暴露量平均值是标准人群2.06倍;安徽省属于花生黄曲霉毒素高暴露地区,该地区标准人群产后花生黄曲霉毒素膳食暴露量平均值是按欧盟和中国标准计算的理论暴露量值的48.3倍和4.83倍,在风险管理中应予以重点关注。3.基于中国产后花生黄曲霉毒素污染分布和污染数据库,采用建立的花生黄曲霉毒素风险评估方法,评估了中国产后花生黄曲霉毒素膳食摄入风险。在中国不同年龄人群中,45岁以上中老年人群产后花生膳食摄入风险最大,乙肝表面抗原阳性中老年人群膳食摄入风险平均值和97.5百分位值分别为0.1356例癌症/100000人·年和0.2169例癌症/100000人·年,占中国年肝癌发病率的0.6%和0.96%。不同花生主产省中,安徽省人群产后花生摄入风险最大,安徽省18岁⁴5岁人群产后花生膳食摄入风险平均值和97.5百分位值分别为0.1693例癌症/100000人·年和1.932例癌症/100000人·年,占中国年肝癌发病率的0.75%和8.59%。四大花生主产区中,长江流域主产区花生膳食摄入风险最大,该区域18岁⁴5岁人群膳食摄入风险平均值和97.5百分位值分别为0.00641例癌症/100000人·年和0.05977例癌症/100000人·年,占中国年肝癌发病率的0.03%和0.27%。除个别地区的高风险人群外,中国产后花生黄曲霉毒素膳食摄入对肝癌的贡献率不足1%,说明花生生产和收获过程中产生的黄曲霉毒素污染对人群花生膳食摄入风险小,需进一步开展花生流通、储藏过程中黄曲霉毒素污染风险评估,摸清花生黄曲霉毒素的主要污染环节,保障花生消费安全和出口贸易。更多还原

【Abstract】 Peanut is the major oil crop and predominant agro-product for export and no import in China, whose production ranks the first among all kinds of oilseeds in the country. As the main cash crop used as both food and vegetable oil, peanut plays an important role in China. However, aflatoxin contamination has been threatening consumption safety and international trade during the recent years, and become the grave potential risks to prevent consumption safety and industry development of peanut. Therefore, for aflatoxin contamination in peanut in China, it’s important to discover the current contamination and develop risk assessment technology for quality & safety supervision, standards setting & revision and exporting trade of agro-products such as peanuts.In the thesis, the distribution of aflatoxin contamination in post-harvest peanut in China was firstly, systematically researched. Collected from 13 main provinces of peanut production covering 90% of peanut production area in the country, 2571 peanut samples were analyzed with an international advanced method of immuno-affinity-liquid-chromatography. And, of aflatoxin contamination in post-harvest peanut in China, the single and total contaminants, contaminated area distribution and contamination features were discovered. Based on the data of aflatoxins contamination in post-harvest peanut and peanut consumption levels in China, the protocol of risk assessment was developed, comprised of ultra-trace data processing method of aflatoxin contamination in peanut and non-parametric quantitative probabilistic assessment as the nuclear techniques. The developed protocol not only accorded with generic international rules, but also was applicable for aflatoxins contamination in peanut in China. With this protocol, dietary intake risk of aflatoxin in post-harvest peanut in China was assessed. So here provided a key technical support for quality & safety supervision, setting & revising standards, and exporting trade and negotiations of Chinese agro-products such as peanuts.The main research methods and results were summarized as the below.1. For the first time, the distribution of aflatoxin contamination in post-harvest peanut in China was discovered and the database of aflatoxin contamination in peanut was constructed. With a stratified random sampling method, 2571 peanut samples were collected in 2009 and 2010 from the country’s main production areas. The samples were detected by the international advanced immunoaffinity-liquid chromatographic method, from which 12855 data of aflatoxin contamination were acquired. The database of aflatoxin contamination in post-harvest peanut in China was developed based on Microsoft.net framework 2.0 and SQLite, which could be written, revised, browsed and searched, input and output data, with the features of few resources occupation and easy maintenance. The database could be conveniently called by @risk to analyze the distribution of aflatoxin contamination in peanut and assess risk assessment of aflatoxin. It was shown that aflatoxin B₁ （AFB₁） is the dominating contaminant in Chinese post-harvest peanuts, averaged 86.2% of the total aflatoixns with a correlation coefficient of 0.99. For aflatoxins contamination levels of post-harvest peanuts, the highest was in Anhui province and the lowest in Liaoning province; the highest in Yangtze River ecological region and the lowest in North-East ecological area, and the results indicated that the aflatoxins contamination levels of post-harvest peanuts in China exhibited apparently regional characteristics, and inferred a tendency that the heavy contamination region has been spreading to north.2. A dietary exposure assessment technique of aflatoxin in peanut in China was developed with the core of ultra-trace data processing method of alternative point value of“0”and“LOD”and non-parametric probability assessment technique. It was proven that the key limit factor on ultra-trace data processing of aflatoxin contamination were aflatoxin analysis method and its limit of detection. After optimization and screening of point value substitute methods such as 0, 1/2 LOD and LOD and of 37 kinds of distribution substitute methods such as Pearson and Lognormal distribution and so on, a constant value method of aflatoxins contamination of 0 and LOD alterative was developed based on the detection method of immunoaffinity-HPLC. And based on the constant value method of 0 and LOD alterative, a non-parametric probability technique was developed. An iterative simulation with 30000 times and sampling with 1000 times were selected after optimization for the non-parametric probability assessment. With the developed non-parametric probability assessment method, the dietary exposure of Chinese post-harvest peanuts was assessed. The result indicated that children belonged to the group with high exposure of aflatoxin in post-harvest peanut, averagely, with 2.06 times of the standard population’s dietary exposure of aflatoxin, and that Anhui province belonged to the area with high exposure of aflatoxin in peanut, in which the standard population’s dietary exposure dose of aflatoxin in post-harvest peanut was 48.3 and 4.83 times of that of European Union and that of Chinese standards respectively. So it needs more attention during governmental risk management.3. The dietary intake risk of aflatoxin post-harvest peanut in China was assessed with the developed method of risk assessment for aflatoxin in peanut based on the distribution and the database of aflatoxin contamination in post-harvest peanut in China. Among the groups classified by ages, it was the highest of the post-harvest peanut dietary intake risk for the group of persons in middle and old age, over 45 years old. For the persons in middle and old age with positive hepatitis B surface antigen, the average risk value and P97.5 value were 0.1356 cases per 100,000 persons per year and 0.2169 cases per 100,000 persons per year, which were 0.6% and 0.96% of the yearly liver cancer incidence in China. Among the main peanut production provinces, it was the highest of the post-harvest peanut dietary risk for Anhui Province people. For the group of 18⁴5 years old people in Anhui, the average risk value and P97.5 value were 0.1693 cases per 100,000 population per year and 1.932 cases per 100,000 population per year, which were 0.75% and 8.59% of the yearly liver cancer incidence in China. Among the four biggest peanut economic areas, it was the highest of the peanut dietary intake risk in the Yangtze River area. The average risk value and P97.5 value for the group of 18⁴5 years old people in this area were 0.00641 cases per 100,000 persons per year and 0.05977 cases per 100,000 persons per year, which were 0.03% and 0.27% of yearly liver cancer incidence in China.In addition to high-risk groups in individual districts, the dietary intake of aflatoxin in post-harvest peanut in China contributed to liver cancer less than 1% except for the persons with high risk in few districts. The results indicated that the post-harvest peanut dietary risk were low, which caused by peanut production and harvesting process, and that further studies need to be focused on the process of peanut circulation and storage for aflatoxin contamination risk assessment, to clarify main process caused aflatoxin contamination in peanut and to protect peanut consumption safety and export trade.更多还原